Grinding machines



Nov, 25, I969 J. P. MILLS GRINDING MACHINES l4 Sheets-Sheet 1 Filed Jan. 19, 1967 Nov. 25, 1969 J. P. MILLS GRINDING MACHINES 14 Sheets-Sheet Filed Jan. 19, 196'? Nov. 25, 1969 J. P. MILLS GRINDING MACHINES l4 Sheets-Sheet Filed Jan. 19, 1967 14 Sheets-Sheet 4 Filed Jan. 19, 1967 mm QNN Nov. 25, 1969 J. P. MILLS GRINDING MACHINES 14 Sheets-Sheet 5 Filed Jan. 19, 1967 New. 25, WW .1. P. MILLS GRINDING MACHINES l4 Sheets-Sheet 8 Filed Jan. 19, 1967 MHH H Nov. 25, 1969 J. P. NHLLS 3,479,773

GRINDING MACHINES Filed Jan. 19, 1967 14 Sheets-Sheet 7 Nmv. 25, 1969 J. P. MILLS GRINDING MACHINES 14 Sheets-Sheet 8 Filed Jan. 19. 1967 mNN I u N3 m WW I m? A I 5% l Ill $3 N5 Q A v\ k (IIIIIIIIL Nov. 25, 1969 J. P. MILLS GRINDING MACHINES 14 Sheets-Sheet 9 Filed Jan. 19, 1967 Nov. 25, 1969 J. P. MILLS 3,479,773

GRINDING MACHINES Filed Jan. 19, 196? 14 Sheets-Sheet l0 Nov. 25, 1969 J. P. MILLS GRINDING MACHINES l4 Sheets-Sheet 11 Filed Jan. 19, 1967 1989 .1. P. MILLS GRINDING MACHINES 14 Sheets-Sheet 12 Filed Jan. l9, 1967 NW. 25, 1969 J. P. MILLS 3,479,773

GRINDING MACHINES v Filed Jan. 19, 1967 14 Sheets-Sheet 13 United States Patent 3,479,773 GRINDING MACHINES John Penrose Mills, Wolverhampton, England, assignor to H. M. Hobson Limited, London, England, a company of Great Britain Filed Jan. 19, 1967, Ser. No. 610,259 Int. Cl. B241) 49/00, 51/00, /00

U.S. Cl. 51165 16 Claims ABSTRACT OF THE DISCLOSURE A grinding machine, for use in particular for the profile grinding of thin walled tubes, which includes mechanism for traversing a workpiece past a rotating profiled grinding wheel and mechanism for rapidly approaching a support for the workpiece towards the grinding wheel, preparatory to grinding, to a predetermined position, and afterwards retracting the support.

This invention provides a grinding machine, and more particularly a grinding machine for use in the profile grinding of fuel cans, which are thin walled tubes intended to contain nuclear fuel elements. The purposes of the grinding operation is to form on the exterior of the tube a number of radially projecting and circumferentially extending cooling fins and all of the fins are formed simultaneously by a profiled grinding wheel. The machine according to the invention may, however, also be used for other purposes, eg. the profile grinding of lands on a solid or tubular rod which is afterwards subdivided into a number of valves.

The grinding machine according to the invention comprises a profiled rotatable grinding wheel, a workpiece carrier adapted to mount a cylindrical workpiece, mechanism for moving the carrier in relation to a support member and so traversing the workpiece past the grinding wheel, mechanism for rotating the grinding wheel, and mechanism for rapidly approaching the support member towards the grinding wheel, preparatory to grinding, to a predetermined position, preferably determined by an adjustable stop, and afterwards retracting it.

Grinding of the workpiece is completed as the result of a single traverse of the workpiece past the grinding wheel. Preferably the movement of the carrier required for such traverse is a rocking movement and is imparted to the carrier by a cam which is so shaped that, during contact of the workpiece with the grinding wheel, the rate of removal of material from the workpiece decreases as the thickness of the workpiece is decreased by grinding.

The support member may be moved bodily on the machine frame towards and away from the grinding wheel under the control of a pair of pneumatic cylinders, containing pistons which are attached to the support member near its ends. Preferably two stops, which are adjustable by micrometer screws, are provided for arresting the inward movement of the support member and the adjustment of these stops will accordingly determine the depth of grinding. The use of such a rapid approach mechanism reduces to a minimum the time required for grinding a workpiece. Hydraulic cylinders or machine driven screws may be used in place of pneumatic cylinders for rapid approach and withdrawal of the support member.

One embodiment of grinding machine according to the invention will now be described in detail, by way of example, with reference to the accompanying drawings, in which:

FIG. 1 is a view showing part of a finished workpiece,

FIG. 2 is a vertical section through the machine,

FIG. 3 is a plan view showing the workheads of the machine,

Patented Nov. 25, 1969 "ice FIG. 4 is a section on the line IVIV in FIG. 3,

FIG. 5 is a section on the line VV in FIG. 4,

FIG. 6 is a section on the line VIVI in FIG. 5,

FIG. 7 is a section on the line VIIVII in FIG. 6,

FIG. 8 is a section on a vertical plane showing the lead screw of the left hand workhead,

FIG. 9 is a section on the line IXIX in FIG. 8,

FIG. 10 is a section on the line X-X in FIG. 9,

FIG. 11 is a section on the line XIXI in FIG. 8,

FIG. 12 is a plan view showing the work steady,

FIG. 13 is a rear elevation of one of the steady motors,

FIG. 14 is a section on the line XIV-XIV in FIG. 13,

FIG. 15 is a vertical section showing mechanism for imparting rocking movement to the workpiece carrier,

FIG. 16 is a sectional elevation of the loading and unloading mechanism looking from the left hand side of the machine as seen in FIG. 3,

FIG. 17 is a vertical section through the same mechanism taken near the right hand end of the machine,

FIG. 18 is a sectional view showing stop mechanism for controlling the movement of the bridge,

FIG. 19 is a section on the line XIXXIX in FIG. 18,

FIG. 20 is a section on the line XX-XX in FIG. 18, and

FIG. 21 is a circuit diagram.

Like reference numerals indicate like parts throughout the figures.

The machine shown in the drawings forms a number of parallel peripheral lands 14A (FIG. 1) simultaneously on a tubular workpiece 14 by a single passage of the workpiece past a rotating profiled grinding wheel 10 (FIG. 2). Said grinding wheel is formed with peripheral grooves, one of which is indicated at 10A in FIG. 2. Since the lands have a width of only 15 thou, and it is diflicult to form in the grinding wheel corresponding grooves of a width less than 30 thou, the workpiece is reciprocated as well as rotated during its traverse past the wheel by mechanism.

As shown in FIG. 2, the machine includes a frame 9 on which the grinding wheel 10 is mounted. In operation the grinding wheel 10 is continuously rotated by an electric motor 11 through a belt drive 8, and workpieces 14 are traversed past in succession by upward arcuate movement past the wheel 10 of a carrier 12 which is mounted on trunnions 120 (FIG. 3) in a bridge 13. Each workpiece is supported during grinding, as later described, by workheads 26 which are reciprocated to and fro on a slide- Way 16 (FIG. 2) on the carrier 12 during the upward movement of the carrier 12. Rotation and reciprocation are imparted to the workpiece during this stage of the cycle by an electric motor 17, which drives a shaft 25 through a belt drive 7, the workpiece rotating in the same direction as the grinding wheel. The carrier 12 is rocked upwardly at the proper time by feeding oil to a pair of hydraulic slave cylinders 18, one at each side of the carrier, and is later allowed to fall by gravity upon exhaustion of oil from the cylinders.

The bridge 13 is reciprocated towards and away from the grinding wheel by a pair of air motors 19, one at each side of the bridge, the extent of inward and outward movement of the bridge being determined by mechanical stops 20, one at each side of the bridge, which are individually adjustable by handwheels 21 and coact with opposite ends of slots 22 in the bridge. Each stop 20 is mounted on a nut 147 engaging a screw 148 attached to the handwheel 21.

As shown in FIG. 2, the bridge 13 is guided at one side only during its reciprocation by a tongue engaging a slot 96 in the machine frame. Movement is transmitted from the motors 19 to the bridge 13 by levers 23 and links 23A. The lower ends of the levers 23 are joined by a torsion bar 24, which is rotatably mounted in the machine frame 9. It is accordingly possible to present the workpiece 14 to the grinding wheel in a slightly oblique position for the purpose of taper grinding by setting the mechanical stops at opposite sides of the bridge 13 to different positions, permitting the unguided side of the bridge to move slightly further than the guided side.

The shaft 25, FIG. 3, driven by the motor 17, carries belt pulleys 36 which drive, through belts 15, belt pulleys 27 on the workheads 26, so imparting rotation to the workheads. The belts 15 are provided with tensioning pulleys 90 (FIG. 4). The shaft also carries a pulley 37 for imparting reciprocating movement to the workpiece as later described. The workheads can be moved towards and away from one another on the carrier 12 to engage and disengage a workpiece by rotation of a shaft 28 having opposite handed screw threads 97 (See also FIG. 5) which engage the workheads. The shaft 28 is rotated, when required, by a rotary air motor 29. The workheads coact respectively with microswitches SW3 and SW4 as described later in more detail. Near the end of the inward movement of the workheads the switch SW4 is actuated to reduce the flow of air to the motor 29, also as later described, and inward movement continues until a stop 30 on the left hand workhead 26 meets a stop 31 on the shaft 28. As shown in FIGS. 8 and 11 the stop 31 is attached to a split nut 150 secured to the shaft 28 by a locking screw 151. The switch SW4 is actuated by abutment of a yoke 153 with the nut 150 and causes restriction in the flow of air to the motor 29 and thereafter the workheads move slowly inward until the faces 154, 155 of the stops meet. This restricted flow of air is maintained to the motor 29 during the grinding operation.

As shown in FIGS. 5-7, each workhead 26 has a body portion 98 in which is mounted, for rotation in bearings 99, a spindle 100 carrying the belt pulley 27. The body portion 98 carries a captive nut 101 engaging the screw threads 97 on the shaft 28 to enable rotation of the shaft 28 to move the workhead 26 to and fro as already described. To permit of fine adjustment of the position of the workhead 26 in relation to the shaft, a wormwheel 102 (FIG. 6) is provided on the nut 101. A spindle 103, rotatably mounted in the workhead, carries a worm 104 engaging the wormwheel 102. Accordingly, by rotating the spindle 103 by application of a wrench to its squared end 105, the nut 101 can be rotated to provide a fine adjustment. The nut 101 can be locked in adjusted position by means of a locking screw 106 (FIG. 7), accommodated in a sleeve 107 and engaging a nut 108. By rotation of the screw 106, the nut 108 can be drawn upwardly on the screw to clamp the nut 101 between itself and the sleeve 107.

The spindle 100 (FIG. 5) carries a spigot 32 for engaging in the end of the workpiece 14 to be ground and a collet 33 for clamping the exterior of the workpiece. A piston has a conical cavity at its left hand end which accommodates the collet 33 and is normally held by springs 34 in a position in which the collet 33 is disengaged from the workpiece. By admitting compressed air to a motor 109, through a passage 110 in the spindle 100, the piston 35 can be forced to the left, as seen in FIG. 5, against the action of the springs 34 to close the collet 33 on the workpiece.

The mechanism for reciprocating the workpiece is shown in FIGS. 8l0. A pulley 38, FIG. 10, mounted on a shaft 111, is driven by a toothed belt 88, shown in FIG. 3, from the pulley 37 on the shaft 25. The shaft 111 rotates, through gearing 112 (FIG. 10), a shaft carrying a cam 39 which is urged by a spring 113 into contact with a ball 42. The shaft 40 is coupled by a coupling 41 to the shaft 28 carrying the workheads 26. As the cam 39 rotates it coacts with the ball 42 to impart reciprocation to the shaft 28, the workheads 26 and the workpiece extending between them. The ball 42 is supported in a fork 114 which can be shifted by a screw 115 to move the ball 42 towards or away from the cam 39. The ball 42 is mounted on a rod 116, which is maintained by a spring 117 in contact with a screw 43. By rotation of the screw 43, the ball 42 can be moved up or down in relation to the cam 39. Adjustment of the degree of reciprocation imparted to the workpiece can accordingly be effected by the screws 43, 115.

The workpiece 14 is supported during grinding by a work steady shown in FIGS. 12-14. This work steady is actuated by four pneumatic motors 118 mounted on the slideway 16 of the carrier 12. The steady includes two fixed lower jaws 44 which support the workpiece throughout its length and two cooperating movable upper jaws 45, each of which is coupled to and operated by two of the motors 118. Each upper jaw 45 is supported by arms 119 projecting from shafts 129 in the associated motors 118. Each shaft 129 carries a quadrant 121, meshing with a rack 122 on the piston rod of a piston 123 accommodated in a cylinder 46. Springs 124 normally urge the pistons 123 inwardly into their respective cylinders and so tend to raise the upper jaws 45. On admission of compressed air into the cylinders 46, however, the pistons 123 will be urged outwardly to lower the jaws 45 into engagement with the workpiece 14.

The mechanism for imparting rocking movement to the carrier 12 to traverse the work-piece 14 past the grinding wheel 10 is shown in FIG. 15. The mechanism is actuated by an electric motor 47 which drives a shaft 125 coupled, by worm gearing 126, gears 127 and worm gearing 128, to a shaft 130 carrying a cam 48. The cam 48 cooperates with a follower 131 on the piston 132 of a master hydraulic cylinder 49, the follower 131 being held in engagement with the cam 48 by a spring 133. When the cam 48 is rotated to the position shown in FIG. 15, it forces the piston 132 to the left to feed oil from the cylinder 49 through pipes 134 to the hydraulic cylinders 18 (FIG. 2). As the result, piston rods 136 in the cylinders 18, which coact with rollers on the carrier 12, are projected from the cylinders 18 to rock the carrier anticlockwise as seen in FIG. 2. The shape of the cam 48 is such that, during contact of the workpiece with the grinding wheel, the rate of removal of material from the workpiece is decreased as the wall thickness of the workpiece is decreased by grinding. As the wall thickness of the tubular workpiece decreases its flexibility and tendency to vibrate increase and it is for this reason that the cam is so shaped as to progressively decrease the rate of removal of material from the workpiece as the latter traverses the grinding wheel. Upon subsequent rotation of the cam 48 through from the position shown in FIG. 15, the carrier 12 will fall by gravity to its original position, returning oil from the cylinders 18 to the cylinder 49.

The machine includes a loading and unloading mechanism shown in FIGS. 16 and 17. The workpieces 14 are stacked in a chute 50 which normally occupies a position, shown in FIGS. 2 and 16, in which the workpieces are prevented from falling out of the chute by a stop 51. Loading and unloading is effected by a pair of arms 52, having sockets 53 to engage the workpiece near its ends, which are carried by a shaft 71 and are movable from a loading position A (FIG. 16) to an unloading position B (FIG. 17).

The loading and unloading mechanism includes an air motor 67, provided with an oil damper 68 having adjustable needle valves 137 for regulating the flow of oil through it. The piston rod of the motor 67 is coupled to a. quadrant 69, pivoted on a pin 138 and meshing with a gear 70 on the shaft 71 which, in addition to the arms 52, carries a cam 72. The motor 67 operates, after grinding of a workpiece has been completed, to rotate the shaft 71 to move the arms 52 from position A to lift the finished workpiece from the lower jaws 44 (FIG. 14) and carry it to position B (FIG. 17)

Towards the end of this movement of the arms 52, the cam 72 actuates a rod 73 (FIG. 16) to rock a rocker arm 74 against the action of a spring 75. The arm 74 is mechanically coupled to the chute 50, and rocking of the arm 74 shifts the chute 50 into the position shown in FIG. 17, so allowing the bottom workpiece in the chute to fall on to toes 76 of the arms 52 in position to fall into the sockets 53 of the arms during their return stroke. Rocking of the arm 74 also actuates a valve V FIG. 16, to supply air from an air supply pipe 140 through a pipe 139 to a motor 77. A delivery tray 78 is supported by links 141, 142 (FIG. 17) on shafts 143, 144. Operation of the motor 77 (FIG. 16) rocks the shaft 144 clockwise through the agency of an arm 80, which also actuates a switch SW Rocking of the shaft 144 shifts the tray 78 from the position shown in full lines in FIG. 17 to that shown in chain-dotted lines and during this movement fingers 79 on the tray lift the workpiece from the sockets 53 in the arm 52 and allow it to roll down the tray to a collection receptacle. Operation of the switch SW causes the motor 67 to move the arms 52 back towards position A. During the early stage of this movement, the spring 75 is allowed by the cam 72 to return the chute 50' to its initial position and the motor 77 returns the tray 78 to its original position. As the arms 52 return they pick up in their sockets 53 the workpiece resting on their toes'76 and on reaching position A they deposit it on the lower jaws of the steady. As the arms reach position A, the cam 72 (FIG. 16) operates a switch SW through an arm 82.

The cycle of operation of the machine will now be explained with reference to the circuit diagram in FIG. 21, in which mechanical connections are shown in heavy dash lines. FIG. 21 shows the motors referred to above for actuating the various components of the machine and the control system includes seven microswitches SW1-SW7, a uniselector US which is a conventional item including relays and contacts which prepare circuits for operation by the microswitches, a number of electromagnetically operated valves COl-COS for controlling the motors, and a number of pressure switches P1P4. Each changeover valve, according to its position, admits air to or relieves air from an associated air motor or motors.

The arms 52 move to the loading position A, FIG. 16, while the carrier 12 is in its up position and the bridge 13 is in its retracted position, to deposit a workpiece 14 on the lower jaws 44 of the steady. Following this the workpiece is engaged by the workheads 26, the upper jaws 45 of the steady close on it and the carrier 12 is lowered. The bridge 13 then commences to move in and the following description of the cycle of operation of the machine starts from this point.

As shown in FIGS. 18-20, the bridge 13 carries two microswitches SW1, SW2, the operating levers 145, 146 of which coact with a fixed stop 54. As soon as the bridge 13 commences to move towards the grinding wheel, i.e. to the left as seen in FIG. 18, the switch SW1 is operated, sending a signal through the line 55, FIG. 21, to the motor 17, so setting the workheads 26 in rotation and imparting rotation to the cam 39 (FIG. 8) for reciprocating the workheads. Inward movement of the bridge 13 is effected, as described above, by the air motors 19 to which air is supplied to drive the bridge in an inward direction through a changeover valve CO Shortly before the bridge completes its inward travel, the switch SW2 is actuated, as shown in FIG. 20 and as the result of contact of a plunger 149 with the stop 54, to reduce the effective areas of throttle valves TV (FIG. 21) in the air circuit to the motors 19 so reducing the speed of travel of the bridge and enabling it to move gently up to its stops 20.

When the bridge has been arrested by the stops 20, the rise in pressure in the air circuit to the motors 19 actuates a pressure switch P This sends a signal through the line 56 to start the electric motor 47 (FIG. 15) for imparting grinding feed, i.e. raising the carrier 12 to traverse the rotating workpiece past the grinding wheel. The switch SW7 is actuated by a cam 58, FIG. 15, on the shaft 130 upon upward movement of the carrier and this causes a signal to be sent through the line 59 (FIG. 21) to switch off the motor 47 and another signal to be sent through the line 60 to reverse the position of the changeover valve C0 The motors 19 accordingly commence to retract the bridge 13 from the grinding wheel. As the result the switch SW2 (see also FIG. 18) is operated to send a signal through the line 61 to switch off the workhead driving motor 17.

As the bridge approaches its retracted position, the switch SW1 (see also FIG. 18) is operated to send a signal through the line 62 to operate the throttle valves TV and so slow down the bridge, and to send another signal through the line 63 to the changeover valve CO moving this valve to release air from the collet actuating motors 109 (see also FIG. 5). These accordingly release the collets 33 holding the workpiece to the workheads. The resulting fall in pressure in the air circuits to the motors 109 operates the pressure switch P to send a signal through the line 64 to a changeover valve CO associated with the rotary motor 29 (see also FIG. 3) to cause this motor to separate the workheads. On-OlT valves V V are interposed between the valve CO and the motor 29 and during separation of the workheads air flows to the motor through the valve V As the workheads separate, the switch SW3 (FIG. 3) is operated to send a signal through the line 65 to close the valve V and thus stop the motor 29 and to send another signal through the line 66 to the changeover valve CO associated with the steady actuating motors 118 (see also FIG. 12). These motors accordingly operate to raise the upper jaws 45 of the steady leaving the workpiece resting on the fixed lower jaws 44. The fall in air pressure in the circuit to the motors 118 as the steady opens operates the pressure switch P to send a signal through the line 57 to the changeover valve CO so causing the pneumatic motor 67 (FIG. 16) to operate. As previously explained, this causes the arms 52 to swing from position A to lift the workpiece from the lower jaws 44 of the steady and carry them towards the unloading position B.

When the valve V is operated, as previously explained, to supply air to the motor 77, the switch SW6 is operated by the arm (FIG. 16) to send a signal through the line 81 (FIG. 21) to the changeover valve CO reversing this valve and causing the motor 67 (FIG. 16) to move the arms 52 back towards position A as previously explained. When the switch SW5 is operated upon return of the arms 52 to position A, it sends a signal through the line 83 (FIG. 21) to the changeover valve 00,, reversing the valve and causing the motors 118 to close the steady. After the steady has closed the pressure switch P sends a signal through the line 84 to the changeover valve CO reversing this valve and sending air to the rotary motor 29 through the valve V to cause the motor to approach the workheads 26. When the workheads have nearly completed their inward movement the switch SW4 (see also FIGS. 3 and 8) is operated to close the valve V As the result air is supplied to the motor 29 through a restrictor 85 only. The bleed through the restrictor causes slow final approach of the workheads to the workpiece and the motor 29 remains stalled after arrest of the workheads by engagement of the stops 30, 31. The rise of air pressure upon stalling of the motor 29 actuates the pressure switch P which sends a signal through the line 86 to the changeover valve CO reversing this valve and causing the motors 109 to close the collets 33 of the workheads. When the collets have closed, the pressure switch P sends a signal through the line 87 to start the motor 47 to withdraw the cam 48 (FIG. 15) and allow the carrier 12 to move to its lower position. As the result the switch SW7 is actuated again by the cam 58 to send a signal through the line 59 to stop the motor 47 and a signal through the line 60 to reverse the changeover valve CO and so cause the motors 19 to initiate inward movement of the bridge.

The valves V V are reopened and the throttle valves are rendered inoperative under control of the uniselector system US at the proper times in the machine cycle.

What I claim as my invention and desire to secure by Letters Patent is:

1. A grinding machine comprising a profiled rotatable grinding wheel, a support member, a workpiece carrier mounted on said support member for movement thereon and adapted to mount a workpiece, mechanism for moving the carrier with respect to said support member to traverse the workpiece past the grinding wheel, mechanism for rotating the grinding wheel, and mechanism for rapidly approaching the support member towards the grinding wheel, preparatory to grinding, to a predetermined position and afterwards retracting it away from the grinding wheel.

2. A grinding machine as claimed in claim 1 in which the movement of the carrier on the support member is imparted to the carrier by a cam so shaped that, during contact of the workpiece with the grinding wheel, the rate of removal of material from the workpiece decreases as its size is decreased by grinding.

3. A grinding machine as claimed in claim 2, comprising two hydraulic slave cylinders connected to the carrier and a master cylinder containing a piston operable by the cam to feed liquid to and exhaust liquid from the slave cylinders, the cam being arranged to raise the carrier when the support member is approached to the grinding wheel and to allow the carrier to fall by gravity when the support member is retracted.

4. A grinding machine as claimed in claim 1 wherein said workpiece carrier is adapted to mount a cylindrical workpiece with its axis extending parallel to the axis of rotation of the grinding wheel, and which includes mechanism for rotating the workpiece about its axis in the same direction as the grinding wheel is rotated.

5. A grinding machine as claimed in claim 4 which includes mechanism for axially reciprocating the workpiece during its traverse past the grinding wheel.

6. A grinding machine as claimed in claim 1, which includes a drive shaft having oppositely handed screw threads engaging workheads for supporting opposite ends of the workpiece and a reversible motor for rotating the drive shaft.

7. A grinding machine as claimed in claim 6, comprising a cam connected to the shaft and coacting with a fixed abutment and means for rotating the cam independently of the shaft to impart reciprocation to the shaft and workheads.

8. A grinding machine as claimed in claim 1 which includes an adjustable stop for limiting movement of the support member towards the grinding wheel.

9. A grinding machine as claimed in claim 8, in which the support member is guided at one end only for its movement towards and away from the grinding wheel and which includes two independently adjustable stops cooperating with the support member at its opposite ends to limit its movement towards the grinding wheel.

10. A grinding machine as claimed in claim 1, comprising a work steady for supporting the workpiece and including a fixed lower jaw and a movable upper jaw.

11. A grinding machine as claimed in claim 10, which includes a loading and unloading mechanism comprising a chute for supporting a stack of workpieces, a pair of pivoted arms arranged to receive the workpieces in succession from the chute and mechanism for rocking the arms while the support member is retracted to deposit on the fixed steady jaw a workpiece collected from the chute and for rocking the arms in the reverse direction, after grin-ding has been completed, to discharge the ground workpiece.

12. A grinding machine as claimed in claim 1 wherein said workpiece carrier is mounted on said support member for rocking movement thereon about an axis parallel to the axis of rotation of the grinding wheel.

13.A grinding machine as claimed in claim 12, wherein said workpiece carrier is adapted to mount a cylindrical workpiece with its axis extending parallel to the axis of rotation of the grinding wheel, and which includes mechanism for rotating the workpiece in the same direction as the grinding wheel is rotated.

14. A grinding machine as claimed in claim 13, which includes an adjustable stop for limiting movement of the support member towards the grinding wheel.

15. A grinding machine as claimed in claim 1, in which the carrier carries rotatable workheads, movable thereon, for supporting and rotating opposite ends of the workpiece and a steady for supporting the workpiece between the workheads, and which includes a motor for moving the support member to and fro, a motor for moving the carrier in relation to the support member, a motor for moving the workheads towards and away from the workpiece, a motor for closing the workheads on the workpiece, a motor for rotating the workheads, a motor for opening and closing the steady and an automatic control system for effecting sequential operation of the motors to engage the workheads with the workpiece and to close the workheads and the steady, to lower the carrier, to approach the support member to the grinding wheel, to set the workheads in rotation, to raise the carrier, to retract the support member from the grinding wheel, to open the workheads and move the latter apart and to open the steady.

16. A grinding machine as claimed in claim 15, which includes an automatic loading and unloading mechanism arranged to deposit workpieces in succession on the steady while the support member is retracted and afterwards to remove ground workpieces from the steady.

References Cited UNITED STATES PATENTS 6/1943 Rickenmann 51-105 5/1959 Rus et a1 5116S X LESTER M. SVVINGLE, Primary Examiner 

